Imaging short period variations in lava flux

Abstract

Short period (e.g. <1 h) variations in lava effusion rate have been detected previously on Mount Etna, Sicily, but the causes and effects of such changes are poorly understood because of difficulties in obtaining suitably high frequency measurements over long periods. Here, we report short period flux variations in active lava flows, recorded in dense time series imagery over a 7-night period using modified remote trail cameras. The sequences of night-time images show significant pulses of enhanced incandescence, interpreted as short period increases in lava flux, travelling down-channel at velocities of ∼10–20 m min−1. Pulse generation decreased from an average of one pulse per hour on the first night to approximately one per night within a few nights. Effusion rate changes on these timescales are considered to reflect instabilities in magma ascent and, consequently, could provide insight into subsurface flow processes.